Theoretical study of The Factors influencing on the Kinetic of 1, 3-Dipolar Cycloadditions Reaction using Quantum Calculation methods

Abstract

Quantum calculations methods like (DFT/B3LYP) and molecular mechanics
(MM2) were carried out to study the molecular geometry and electronic structure of
(1, 3- dipolar cycloadditions of thalazinium-2-dicyancmethanide) (1) as a 1, 3- dipole
with nine series of dipolarophiles electron-rich, electron- poor. The different
investigated electronic properties of nine series includes, electron densities of the
carbons involved in the addition reaction ,the frontier orbital energy levels, the steric
energy of the transition states and products, were correlated as independent variables .
The rate constants of addition are correlated as dependent variable. Single and multiparametric
linear regression analysis are studied the influence of these different
electronic properties on the kinetic of 1, 3- dipolar.
Result of the analysis reveal that all mentioned factors affect the rate of the
reaction but to different extents. The steric energy of transition state, the highest
occupied molecular orbital HOMO, and steric of product most influencing factors.
The lowest unoccupied molecular orbital LUMO, electron densities of carbon one and
two involved in addition has the least influence on the reaction rate.